Insomniac dudes confirmed here on GAF that it was an optional amp ages ago. I'd assume it's just not something you unlock in the parts of the game that people are allowed to show pre-release.
One thing I've noticed is that a lot of the people streaming the game right now are kinda terrible at it, which isn't helping with how fast it looks.
It looks a lot faster and more fluid when there's someone who's actually got the hang of the controls and is properly chaining traversal moves together is behind the controller. Check out the traversal challenges at the start of
this video, for example.
That guy's other videos (
youtube,
twitch) are probably the best examples I've seen yet of someone
actually playing the game well (and this is still early-game footage with some moves locked, ie, I haven't seen the airdash they've shown in SunsetTV in any of the prerelease streams yet).